1. Field of the Invention
This invention relates to the field of miniature automobile racing and specifically the need for a drivable wheel hub assembly, capable of supporting the driven wheels, independent of the drive axle.
2. Description of the Related Art
Miniature race cars such as what is known as a Dwarf Car and Legends race cars use a rigid or non-independent rear drive axle system. The most commonly used rear drive axle system for these cars is called a Toyota "ten bolt." This drive axle system is common in a variety of small passenger cars produced by Toyota. It is modified for use in miniature race cars by moving the differential over to the right side of the car. This is done to facilitate coupling of the differential to the engine. The Toyota rear drive axle is chosen because of its compact size and light weight making it compatible within the confines of the miniature race cars chassis configuration. It is also in abundant supply at automotive salvage yards keeping costs affordable.
The problem with this type of drive axle system is that the drive axle functions as the rotating support for the wheel and also transmits rotational energy from the differential to the wheel. This makes it possible for the drive wheels to escape from the car if drive axle failure occurs during vehicle operation. Another disadvantage with this system is by its design it takes a significant amount of time to remove the drive axles from the axle housing. This is undesirable because the differential gears are changed frequently for different sized race tracks and the drive axles have to be removed each time to change them.
Solving this problem has previously been approached by utilizing what is known as a "full floating axle assembly." For example, U.S. Pat. No. 4,351,407 to Call (1982) discloses such an assembly which has generally been in use on large vehicles such as trucks. U.S. Pat. No. 5,197,786 to Eschenburg (1993) discloses a similar assembly designed for use in race cars. Stock Car Products Co., Inc. also manufacturesa full floating axle assembly resembling the patents mentioned above.
All of these systems are functional but fail to be widely used in miniature race cars because of a number of significant problems. One such problem with these systems is that they were primarily designed for larger sized vehicles, for instance, trucks and Nascars' Winston Cup and Grand national Series race cars. It is possible to use these systems in miniature race cars by using a larger drive axle assembly. For example, a Nissan small truck axle assembly can be modified to accept Stock Car Products full floating axle assembly and can be fitted into a miniature race car. The disadvantages of doing this is that it adds significant unwanted weight to the race car and requires specialized equipment, such as, alignment fixtures and welders to be installed. Also, there are fewer supplies of these small truck axle assemblies available through automotive salvage yards. Accordingly, these disadvantages increase the expenses involved with applying these systems to miniature race cars.